Bukkit

Set up redstone wires as high voltage cables to protect areas

Trade with players or a global shop for dynamic prices, using commands or signs. Supports all economy plugins.

Your lifetime is your currency!

Send player messages, if they take a specific item in the hand or off

Set up any mob you want as guard to protect areas from mobs and griefers!

Disable hunger, damage and sprint exhaustion with permissions. Very lightweight!

Write commands in chat and the console will execute them!

Freeze the ground, players, mobs and moving things like arrows

Jump as high as you want!

Spawn ANY mob behind one or all players with infinite amount!